Stabilized hydroxylamine solutions

ABSTRACT

A stabilized hydroxylamine solution is disclosed. The stabilized solution comprises a selected stabilizer, which can be added during manufacture and/or storage of the hydroxylamine solution.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a stabilized hydroxylamine solution, and more particularly, to a hydroxylamine solution, which comprises a selected stabilizer.

[0003] 2. Description of the Related Art

[0004] Hydroxylamine, especially in the form of its salts with sulfuric acid, hydrochloric acid and others, is an important intermediate for the chemical industry, and is widely employed in chemical syntheses. It is frequently necessary to employ hydroxylamine in the form of a solution of the free base, which is generally liberated from a hydroxylammonium salt such as, for example, hydroxylammonium sulfate or hydroxylammonium chloride, by the action of an appropriate base, such as ammonia, sodium hydroxide solution or an alcoholate. Neutral and alkaline hdyroxylamine solutions are unstable and decompose to form ammonia, nitrogen, oxides of nitrogen and water, so that their transportation or storage is highly problematic. The rate of decomposition increases with rising temperature, rising hydroxylamine concentration, rising pH and rising concentration of catalytically active impurities.

[0005] In Order to avoid the decomposition of the hydroxylamine, a stabilizer is added to the solutions. Numerous stabilizers for hydroxylamine are already known. Proposals which have been made are: thioglycolic acid (JP-A-58069843), glycerol monethers and ethylene oxide adducts thereof (DE-A-29 19 554), hydroxyanthraquinones (DE-A-33 43 600), hydroxyquinolines (DE-A-33 45 734), polyhydroxyhexano-1,4-lactone (DE-A-33 45 733), anthocyanins (DE-A-33 47 260), hydroxyquinaldines, flavones, benzonitrile, N-phenyl-N hydroxythiourea (DE-A-36 01 803), flavans (DE-A-33 43 599), thiosulfates, mercaptobenzothiazoles, mercaptoalkanols, mercaptothiazolines, thiuram disulfides, thioureas (EP-A-516 933), the tetrasodium salt of ethylenediaminetetraacetic acid, the trisodium salt of N-hydroxyethylenediaminetriacetic acid, polyvinylpyrrolidone or poly-N-vinyl-5-ethyl-2-oxazolidinone (U.S. Pat. No. 3,145,082), amide oximes (U.S. Pat. No. 3,480,391), hydroxamic acids (U.S. Pat. No. 3,480,391), hydroxyureas (U.S. Pat. No. 3,544,270), dipyridyl compounds (JP-A-58069842), aminoquinolines (JP-A-58069844), phenanthrolines (JP A-58069841), and polyhydroxyphenols (JP-A-4878099).

[0006] However, none of the stabilizers proposed to date has been able to provide hydroxylamine solutions with sufficient stabilization to prevent excessive decomposition of the hydroxylamine to occur, especially during storage.

[0007] What is desired and needed is a better means for stabilizing a hydroxylamine solution.

DETAILED DESCRIPTION OF THE INVENTION

[0008] This Invention relates to a stable hydroxylamine solution, and more particularly, to such a solution, which comprises a selected stabilizer.

[0009] Hydroxylamine is prepared commercially by the Raschig process or variations thereof, in which ammonium or sodium nitrite is reacted in aqueous solution with ammonium or sodium bi-sulfite and sulfur dioxide. The resulting disulfonate salts are subsequently hydrolyzed to a solution containing essentially hydroxylammonium sulfate, sulfuric acid, ammonium sulfate and/or sodium sulfate plus minor amounts of the corresponding nitrate. This solution can be used, after neutralization with a base, as a source of hydroxylamine or pure hydroxylammonium salts from the mixture.

[0010] A suitable selected stabilizer is selected. A suitable selected stabilizer is a compound which complexes or chelates metals, such as for example, Ca, Fe, Zn, Al, Cu, Ni, etc., which catalyze the decomposition of an aqueous hydroxylamine solution during its manufacture, storage and transportation. Such a stabilizer includes (a) diethylenetriaminepentaacetic acid (“DPTA”), (b) triethylenetetraminehexaacetic acid (“TTHA”), (c) ethylene-bis(oxyethylenentirilo)tetraacetic acid (“EGTA”), (d) 1,4,8,11-tetraazacyclotetradecane-1,4,8-11-tetraacetic acid, (e) 4,8-dihydroxyquinoline-2-carboxylic acid, (f) 4,5-dihydroxy-1,3-benzene-disulfonic acid, (g) 4,7-dihydroxy-1,10-phenanthroline, (h) 2-mercaptonicotinic acid, (i) bis[N,N′-bis(carboxymethyl)aminomethyl]fluorescein [fluorexon], (j) N,N-bis(2-carboxyethyl)-N,N′ethylenediglycine trihydrate, (k) Cystine, (1) 2,3-dihydroxybenzoic acid, (m) Thiosalicyclic acid, (n) a mixture of the any of the foregoing compounds and (n) and the salts of any of the foregoing compounds. Particularly preferred salts of the selected stabilizers include amine salts, e.g. triethylamine, triethanolamine; hydroxyamines; acid addition salts with inorganic acids, e.g. HF, HCl, HBr, H₂SO₄, H₃PO₄, etc., if basic functions are present.

[0011] The selected stabilizer is added or combined either with the reactants during the process for manufacturing the hydroxylamine solution, or during the storage of a basic or neutralized aqueous solution of such manufactured hydroxylamine.

[0012] The selected stabilizer is added to the reactants, e.g. Raschig process reactants, or to a neutral or basic aqueous hydroxylamine solution, e.g. in excess of 50-weight percent hydroxylamine solution, in an amount sufficient to stabilize the hydroxylamine solution. By “stabilize” is meant that the hydroxylamine concentration in the neutral or basic solution does not decompose or decrease by 2.0 weight percentage in a time period of 24 hours at a temperature of 25° C. Typically, the final concentration of the added selected stabilizer is present in the resultant neutral or basic hydroxylamine solution in an amount ranging from about 0.005 percent to about 0.1 percent by weight to the total weight of the resultant solution. In this regard, the concentration of hydroxylamine is in general 1-100% by weight, in particular 1-70% by weight, based an the overall weight of the resultant solution.

[0013] It is to be pointed out that the selected-stabilizer can be used as a single selected stabilizer or as a mixture of at least two selected stabilizers. Additionally, the selected stabilizer or stabilizers (mixture) can be combined with other well known stabilizer, such as, thioglycolic acid, glycerol monethers and ethylene oxide adducts thereof, hydroxylanthroquinones, hydroxyquinolines, polyhydroxyhexano-1,4-lactone, anthocyanins, hydroxyquinaldines, flavones, benzonitrile, N-phenyl-N-hydroxythiourea, flavans, thiosulfates, mercaptobenzothiazoles, mercaptothiazolines, thiuram disulfides, thioureas, the tetrasodium salt of ethylenediaminetetraacetic acid, the trisodium salt of N-hydroxyethylethylenediaminetriacetic acid, polyvinylpyrrolidone or poly-N-vinyl-5-ethyl-2-oxazolidinone, amide oximes, hydroxamic-acids, hydroxyureas, dipyridyl compounds, aminoquinolines, phenanthrolines, and polyhydroxyphenols. In this regard, reference is also made to U.S. Pat. No. 5,783,161, which reveals other stabilizers. Stabilizer for H-Base Weight Loss Screening Test Hydroxylamine (HA) and Ammonia Determination after Weight Loss Screening Test % HA % ammonia Wt % wt remaining after formed during 1997 stabilized 56% HA + Fe(III) + Candidate loss g loss screening test screening test comment Diethylenetriaminepentaacetic acid 0 0 56 0 Triethylenetetraminehexaacetic acid 0 0 55 0 (TTHA) Ethylenebis(oxyethylenenitrilo)tetra- 0 0 52 0 acetic acid (EGTA) 1,4,8,11-tetraazacyclotetradecane- 0 0 54 0 1,4,8,11-tetraacetic acid 4,8-dihydroxyquinoline-2-carboxylic 0 0 54 0 acid 4,5-dihydroxy-1,3-benzenedisulfonic 0 0 54 0 Rose color acid Thiosalicylic acid 0 0 54 0 Light yellow Salicylic acid 0.26 21 18 3.4 Light yellow 2-mercaptonicotinic 0 0 54 0 2-carboxyethylphosphonic acid 0.2 16 19 4.7 cystine 0 0 52 1.1 4,7-dihydroxy-1,10-phenanthroline 0.01 0.8 51 1.1 Redish color 1,4,8,11-tetraazacyclotetradecane- 0.06 4.9 42 3.2 5,7-dione Fluorexon or {bis[N,N-bis(carboxy- 0.01 0.8 54 0 color methyl)-aminomethyl]fluorescein} 1997 stabilized 55% HA 0.34 28 16 2.2 “no candidate” CDTA 0 0 55 0 N,N′-bis(2-carboxyethyl)- 0 0 55 0 N,N′-ethylenediglycine trihydrate Inositolhexaphosphoric acid 0.12 10 28 5 2,3-dihydroxybenzoic acid 0.02 1.6 50 1.6 Some loss of sample before titation

Gas Evolution Method

[0014] General Procedure: 4 mL glass vial on Top Loading Balance, 2 mL of Fe(III) [356 mg Fe(III) Sulfate-Hydrate/10 mL H₂O {circumflex over (=)}5000 ppm Fe(III)] add to 10 mL plastic beaker with micro stirrer, 100 mL of water or new stabilizer usually at 10000 ppm, 1 mL of either stabilized oder destabilized HA (1997 56%) contents transferred to glass vial+wt loss monitored vs. Time 1997 destabilized 2,6-Pyridinedicarboxylic 1997 stabilized min. 1997 destabilized acid H₂O 0 6.07 wt loss 0 6.02 0 6.01 1 6.06 5 6.01 .01 3 6.03 0.01 2 6.06 .01 10 5.99 .03 5 5.98 0.06 5 5.98 .09 12 5.99 .03 6 5.90 0.14 7 5.93 .14 14 5.97 .05 10 5.77 0.27 11 5.91 .16 17 5.57 .05 11 5.77 0.27 18 5.90 .17 18 5.96 .06 12 5.76 0.28 21 5.89 .18 23 5.95 .07 13 5.77 0.27 24 5.89 .18 29 5.94 .08 14 5.76 0.28 30 5.88 .19 33 5.93 .09 20 5.76 0.28 36 5.88 .19 43 5.91 0.11 26 5.75 0.29 40 5.88 .19 54 5.91 0.11 30 5.25 0.29 51 5.87 0.20 42 5.74 0.30 61 5.86 0.21

Gas Evolution

[0015]  2 mL 5000 ppm U4A15 U4A13 U4A9 1997 SW U4AW Fe(III) 1.63 mg 1.98 mg 2.21 mg 2.02 1.5 100 mL H₂O 99.18 mg 99.9 100.2 mg 99.9 99.2 or 10,000 ppm water Stabilizer  1 mL HA 1189.9 mg 1170 mg 1173 mg 1199 1182 Vial 4.90 g 4.85 4.85 4.88 4.81 6.02 1 6.04 1 5.86 1 5.95 0 1 6.02 1 5.97 0 2 6.04 2 5.82 0 2 5.95 0 2 6.02 0 2 5.97 0 3 6.03 0.01 3 5.87 −0.01 3 5.95 0 3 6.00 0.02 3 5.96 0.01 4 6.02 0.02 4 5.87 −0.01 4 5.95 0 4 5.95 0.07 4 5.95 0.02 5 5.99 0.05 5 5.87 −0.01 5 5.95 0 5 5.86 0.16 5 5.92 0.05 6 5.95 0.01 6 5.87 −0.01 6 5.95 0 6 5.79 0.03 6 5.89 0.05 7 5.93 0.11 7 5.87 −0.01 7 5.95 0 7 5.78 0.24 7 5.85 0.12 8 5.91 0.13 8 5.87 −0.01 8 5.95 0 8 5.77 0.25 8 5.82 0.15 9 5.91 0.13 9 5.87 −0.01 9 5.95 0 9 5.76 0.26 9 5.82 0.15 10 5.90 0.14 10 5.86 0 10 5.95 0 10 10 5.81 0.16 11 5.90 0.14 11 5.86 0 12 5.95 0 11 5.75 0.27 11 5.81 0.16 15 5.88 0.16 15 5.87 −0.01 15 5.95 0 15 5.80 0.17 29 5.87 0.17 29 5.87 −0.01 29 5.94 0.01 35 5.73 0.29 31 5.78 0.19

Gas Evolution

[0016] Aldrich 1997SW 50% HA U4AW U4A16 U4A22 2 mL Fe(III) 1.97 mg 2.02 1.89 mg 2.16 mg 1.87 mg 5000 ppm 100 mL water 102.4 mg 101.2 mg 101.6 mg 100.5 mg 99.5 mg or new stabilizer H₂O H₂O H₂O 16 22 1 mL HA 1221 1209.7 1195 mg 1200 1194 Vial 4.88 g 4.84 g 4.85 4.82 4.92 0 6.06 0 5.99 0 5.98 0 5.94 0 6.09 1 6.05 0.01 1 5.99 0 1 5.98 0 1 5.94 0 1 6.09 0 2 6.04 0.02 2 5.99 0 2 5.98 0 2 5.94 0 2 6.09 0 3 6.04 0.02 3 5.99 0 3 5.96 0.02 3 5.94 0 3 6.09 0 4 6.02 0.04 4 5.98 0.01 4 5.95 0.03 4 5.94 0 4 6.08 .01 5 5.98 0.08 5 5.98 0.01 5 5.91 9.07 5 5.94 0 5 6.07 .02 6 5.88 0.18 6 5.98 0.01 6 5.87 0.11 6 5.94 0 6 6.07 .02 7 5.82 0.24 7 5.97 0.02 7 5.86 0.12 7 5.94 0 7 6.07 .02 8 5.29 0.27 8 5.95 0.04 8 5.85 0.13 8 5.94 0 8 6.06 .03 9 9 5.95 0.04 9 5.84 0.14 9 5.94 0 9 6.06 .03 10 5.78 0.28 10 5.94 0.05 10 5.84 0.14 10 5.94 0 10 6.06 .03 14 5.88 0.11 15 5.87 0.12 16 5.83 0.16 15 5.94 0 15 6.06 0.04 20 5.76 0.30 20 5.83 0.16 20 5.81 0.15 20 5.94 0 20 6.03 0.05

Gas Evolution Testing of New Stabilizers

[0017] 1997SW 1997S28 1997S29 1997S14 1997S23 1997S4 2 mL Fe(II) 1.61 mg 1.76 mg 1.84 mg 1.92 1.97 2.00 5000 ppm Fe 100 mL water 100.5 mg 100 mg 101.6 mg 97.2 101.9 96.3 or New 28 23 4 Stabilizer 1 mL HA 1225 1220 mg 1221 mg 1221 1230 1222 Vial 4.85 4.81 4.87 4.85 4.91 4.85 Time 0 6.06 5.98 6.06 6.06 0 6.14 0 6.07 min 1 6.06 0 5.98 6.06 6.06 0 1 6.14 0 6.06 .01 2 6.05 .01 5.97 .01 6.05 .01 6.07 −.01 2 6.14 0 6.06 .01 3 6.04 .02 5.96 .02 B 6.05 .01 B 6.06 0 3 6.14 0 6.06 .01 4 6.04 .02 5.95 .03 B 6.03 .03 6.06 0 4 6.14 0 6.06 .01 5 6.00 .06 5.89 .09 VB 6.00 .06 VB 6.06 0 5 6.14 0 6.06 .01 6 5.91 .15 5.83 .15 VB 5.96 .10 VB 6.04 .02 6 6.14 0 6.06 .01 7 5.81 .25 5.79 .19 B 5.94 .12 VB 6.04 .02 7 6.14 0 6.06 .01 8 5.75 .31 5.77 .21 B 5.12 .14 B 6.03 .03 8 6.14 0 6.06 .01 9 5.25 .31 5.76 .22 5.90 .16 6.01 .05 9 6.14 0 6.06 .01 10 5.75 .31 5.89 .17 6.00 .06 10 6.14 0 6.06 .01 15 5.73 .33 5.75 .23 5.86 .20 11 5.93 .13 15 6.14 0 6.06 .01 20 5.72 .34 5.75 .23 5.85 .21 12 5.89 .17 20 6.14 0 6.06 .01 13 5.82 .24 wt loss 0.34 g 0.23 g 0.21 g 14 5.78 .29 wt loss = 0 wt loss = 0.01 15 5.77 .29 1997SW = 1997 Stabilized + 100 mL H₂O 1997S28 = 1997 Stabilized + 100 mL Polystyrene sulfononic acid-comaleicacid sodiumsalt 102.5 mg/10 mL 1997S29 = 1997 Stabilized + 100 mL Polyacrylic acid sodium salt 40% 304.8 mg/10 mL 1997S14 = 1997 Stabilized + 100 mL 2,5-dihydroxy-1,4-benzenediaceticacid 107.4 mg/10 mL 1997S23* = 1997 Stabilized + 100 mL CDTA   105 mg/10 ml H₂O 1997S4* = 1997 Stabilized + 100 mL FLUOREXON 101.3 mg/10 ml H₂O *little or no wt loss: little or no decomposition B = Bubbles V = Vigorous

Gas Evolution

[0018] U4A17 U4A21 U4A19 U4A23 1997S23 2 mL Fe(III) 1.86 mg 1.90 1.90 1.25 1.80 5000 ppm Fe¹³ 100 mL H₂O 100.9 mg 101.3 100.6 11.8 23 11.4 mg 23 or 17 21 19 98.8 H₂O 99.9 mg H₂O New Stabilizer 1 mL HA 1191 mg 1194 1191 1189 1224 Vial 4.96 4.93 4.85 4.84 4.85 0 6.08 0 6.10 0 6.01 0 6.01 0 6.05 1 6.07 0.01 1 6.10 0 1 6.01 0 1 6.01 0 1 6.05 0 2 6.08 0 2 6.10 0 2 6.01 0 2 6.01 0 2 6.05 0 3 6.06 0.02 3 6.09 0.01 3 6.01 0 3 6.01 0 3 6.05 0 4 6.04 0.04 4 6.08 0.02 4 6.01 0 4 6.01 0 4 6.05 0 5 6.02 0.06 5 6.05 0.05 5 6.01 0 5 6.01 0 5 6.05 0 6 6.00 0.08 6 6.01 0.09 6 6.01 0 6 6.01 0 6 6.05 0 7 5.99 0.09 7 5.98 0.12 7 6.01 0 7 6.01 0 7 6.05 0 8 5.97 0.11 8 5.97 0.13 8 6.01 0 8 6.01 0 8 6.05 0 9 5.96 0.12 9 5.96 0.14 9 6.01 0 9 6.01 0 9 6.05 0 10 5.95 0.13 10 5.95 0.15 10 6.01 0 10 6.01 0 10 6.05 0 15 5.94 0.14 15 5.94 0.16 15 6.01 0 15 6.01 0 15 20 5.93 0.15 20 5.93 0.17 20 6.01 0 20 20 6.05 0 U4A17 U = unstabilized 1997, 4^(th) Fraction,   99 mg/10 mL H₂O A 1^(st), 17 N,N′ dicarbocymethyl- diaza-28-crown-6 U4A21 = Krypto Fix 222 106.4 mg/10 mL H₂O U4A19 = Diethylenetriaminepentaacetic 101.4 mg/10 mL acid 28,556-0 UA23 = CDTA   105 mg/10 ml H₂O

[0019] 1997SW U4AW U4A26 U4A25 U4A24 U4A11 U4A14 2 mL Fe(III) 1.94 1.89 1.97 1.99 1.99 1.79 1.88 5000 ppm Fe¹³ 100 mL H₂O 100.6 mg 99.8 99.7 101 95.5 99.1 98.9 mg or 26 25 11 14 New Stabilizer 1 mL HA 1221 mg 1195 1188 1203 Green/ 1207 Yellow Amber Vial 4.84 4.84 4.95 4.95 4.87 4.84 4.93  0 6.04 5.99 6.11 6.07 6.02 6.00 0 6.07  1 6.04 5.99 0 6.11 0 6.07 6.02 0 6.00 0 6.07  2 6.04 5.99 0 6.12 −.01 6.07 6.02 0 6.00 0 6.07  3 6.03 .01 5.98 .01 6.11 0 6.07 6.02 0 6.00 0 6.06 .01  4 6.02 .02 5.97 .02 6.11 0 6.07 6.02 0 6.00 0 6.06 .01  5 5.97 .02 5.93 .06 6.11 0 6.07 6.02 0 6.00 0 6.05 .02  6 5.87 .17 5.91 .08 6.11 0 6.06 .01 6.02 0 5.99 .01 6.05 .02  7 5.80 .24 5.89 .10 6.11 0 6.06 .01 6.02 0 6.00 .01 6.04 .03  8 5.78 .26 5.87 .12 6.11 0 6.06 .01 6.02 0 6.00 0 6.03 .04  9 5.77 .27 5.86 .13 6.12 −.01 6.05 .02 6.02 0 6.00 0 6.02 .05 10 5.76 .28 5.86 .13 6.11 0 6.05 .02 6.02 0 6.00 0 6.01 .06 15 5.75 .29 5.83 .16 6.11 0 6.04 .03 6.02 0 5.99 .01 5.98 .09 20 5.75 .29 5.83 .16 6.12 −.01 6.04 .03 6.02 0 5.99 .01 5.97 .10 1997SW 1997 stabilized water U4AW 1997 destabilized + water U4A26* 1997 destabilized + triethylenetetraamine, 105.6 mg/10 mL N,N,N′,N″,N′″,N′″ hexaacetic acid U4A25 1997 destabilized + inositole hexa-   187 mg/10 mL phosphoric acid 40-50% U4A24* 4,8 dihydroxyguinoline-2-carboxylic  99.6 mg/10 mL acid U4A11* 4,7 dihydroxy-1,10-phenanthroline  51.3 mg/10 mL UA414 2,5 dihydroxy-1,4-benzenediacetic acid 107.4 mg/10 mL

General Titration Procedure

[0020] Determination of remaining NH₂OH after gas evolution Test: General Procedure: First wash contents of 10 mL plastic beaker with 2 mL conc HCl+5 mL H₂O, transfer HCl+washings to 200 ml Volumetric Flask. After completion of-the gas evolution experiment, transfer contents of 4 mL Vial to 200 mL Volumetric Flask. Add 2 ml HCl to Vial wash with 10-20 mL H₂O, Transfer all washings to 200 mL volumetric Flask. Dilute up to Volume. Take 10 mL aliquot and titrate with 0.25 N NaOH. From page 27 calculation for HA=Hydroxylamine 1 mL={circumflex over (=)}1.1 g ${{mL} \times \frac{{.25}\quad {mole}}{1000\quad {mL}} \times \frac{1}{1.1\quad g} \times \frac{33\quad g}{mole} \times \frac{200\quad {mL}}{10\quad {mL}} \times 100} = {\% \quad {HA}\quad {or}\quad {mL} \times 15}$

[0021] 1997SW=1 mL 1997 Stabilized+100 ml H₂O+2 mL Fe⁺³ (5000 ppm)

[0022] 1997S28=Inl 1997 Stabilized+100 mL Polystyrenesulfonate-co-maleic acid, sodium salt+2 mL (Fe⁺³ 5000 ppm)

[0023] 1997S29=1 mL 1997 stabilized+100 ml of {circumflex over (=)}10000 ppm polyacrylic acid sodium salt 40% 304.8 mg/10 mL+2 ml of Fe(III) 5000 ppm

[0024] 1997S14=1 mL 1997 stabilized+100 mL of 2,5 dihydroxy-1,4-benzenediacetic aicd 107.4 mg/10 mL, +2 mL of Fe(III) 5000 ppm

[0025] 1997S23=1 mL 1997 stabilized+100 mL of CDTA 105 mg/10 mL, 2 mL of Fe(III) 5000 ppm

[0026] 1997S4=1 mL 1997 stabilized+100 mL of Fluorexon (11,985-7 Cat# Aldrich 101.3 mg/10 mL+2 mL of Fe(III) 5000 ppm

[0027] HA=hydroxyl amine Note 1997S23+19974 showed little or no decomposition

Gas Evolution

[0028]  2 mL Fe(III) 500 ppm 1997S32 1997S31 1.97 mg 1.93 mg 100 mL H₂O or New Stabilizer 101 mg 101.3 mg  1 mL of 1997S Σ 1218 mg 1222 mg Vial empty 4.93 g 4.89 0 6.10 0 6.09 1 1 6.09 2 6.10 2 6.09 B 3 6.08 B 3 6.08 4 6.08 B 4 6.06 VB 5 6.05 VB 5 6.03 VB 6 6.02 VB 6 5.93 7 6.00 VB 7 5.83 VB 8 5.98 8 5.77 VB 9 5.97 9 5.75 10 5.95 10 5.74 15 5.91 15 5.73 20 5.89 20 5.72 wt loss 0.21 g wt loss 0.37 1997S32 = 1 mL 1997S 1997S31 = 1 mL 1997S 113 mg/10 mL 1,2bis(2 amino phenoxy) ethane 100 ml of Trans-Aconitric acid N,N,N′,N′ tetracetic acid 105 mg/10 mL

[0029]

[0030] B=Bubbles

[0031] V=Vigorous

Gas Evolution+Titration

[0032] Sample 1997S34 1997S35 HA = Hydroxylamine 2 mL Fe(III) 5000 ppm 1.98 mg 1.98 mg Note 1997S35 100 mL New Stabilizer 101 mg 102.5 mg little or NO wt loss 1 mL 1997S Σ 1229 mg Σ 1225 mg in little or NO HA Vial empty 4.90 g 4.82 g decomposition Time Time Min Min 0 6.12 0 6.05 1 6.12 1 6.05 2 6.11 2 6.05 3 6.10 B 3 6.05 4 6.09 4 6.05 5 6.04 VB 5 6.05 6 5.92 6 6.05 7 5.84 VB 7 6.05 8 5.82 8 6.04 B 9 5.81 9 6.04 10 5.80 10 6.05 15 5.79 15 6.04 20 5.79 20 6.03 wt loss 0.33 g wt loss 0.02 g 1 mL 1997S 1 mL 1997S 100 mL 34 = 1,1′-Ethylenebis(5-oxo-3- 100 mL 109 mg pyrrolidine carboxylic acid Cat# 32, 756-S 2,3 dihydroxybenzoic Alrich acid

[0033]

Gas Evolution+Titration

[0034] sample 1997S33 1997S19 1997S36 1997S40 1997S26 5000 ppm Fe 2.17 mg 2.43 mg 2.09 mg 2.11 mg 1.98 mg 2 mL 100 mL 101.8 mg Σ 101.6 mg 100.8 mg 101 mg 100 mg New Stabilizer Σ 1 mL 1997S Σ 1225 mg Σ 1224 mg Σ 1220 mg 1220 mg 1220 mg Vial empty 4.93 g 4.88 g 4.88 g 4.82 g 4.85 g Time Minutes  0 6.13 g 6.09 g 6.10 g 5.95 g 6.07 g  1 6.13 g 6.10 g 6.10 g 5.95 g 6.07 g  2 6.13 g 6.10 g 6.10 g 5.95 g 6.07 g  3 6.12 g B 6.10 g 6.10 g 5.94 g 6.07 g  4 6.10 g 6.10 g 6.10 g 5.92 g VB 6.07 g  5 6.03 g VB 6.10 g 6.10 g 5.89 g VB 6.07 g  6 5.93 g VB 6.10 g 6.10 g 5.83 g VB 6.07 g  7 5.88 g VB 6.10 g 6.10 g 5.78 g VB 6.07 g  8 5.86 g 6.10 g 6.10 g 5.75 g 6.07 g  9 5.85 g 6.10 g 6.10 g 5.73 g 6.07 g 10 5.85 g 6.10 g 6.10 g 5.73 g 6.07 g 15 5.84 g 6.09 g 6.10 g 5.71 g 6.07 g 20 5.84 g 6.10 g 6.10 g 5.70 g 6.07 g wt 0.29 g wt 0 g wt 0 g wt 0.25 g wt 0 g loos loss loss loss loss

[0035]

[0036] Note 1997S19, 1997S36+1997S26 showed little or no wt loss in or no decomposition

Gas Evolution+Titration

[0037] 1997S19=1 mL 1997 Stabilized, 100 mL of Diethylene triamine pentaacetic acid (28,556-0 cat# Aldrich) 101.4 mg/10 mL, 2 mL of 5000 ppm Fe

[0038] 1997S36=1 mL 1997 Stabilized, 100 mL of N,N′-Bis(2-carboxyethyl)-N,N′ethylenediglycine trihydrate (Aldrich 28,584-6)

[0039] 1997S40=1 mL 1997 stabilized, 100 mL 1,2,3,4 Butanetetracarboxylic acid 105.9 mg/10 mL, 2 mL of 5000 ppm Fe

[0040] 1997S26=1 mL 1997 Stabilized, 100 mL Triethylenetetramine N,N,N,N, hexaacetic acid

Gas Evolution+Titration

[0041] sample 1997S9 1997S13 1997S16 1997S22 1997S24 1997S11 1997S25 5000 ppm Fe     1.72 mg 2.07 1.70 2.02 1.89 1.76 2 2 mL New Stabilizer Σ 101.4 mg 101.9 Green 101.2 100 99.7 Greenish 98.4 Redish 99 100 mL Color Color 1997S H-Base  Σ 1220 mg 1221 Rose 1220 1222 1218 Yellow 1215 1224 55% HA 1 mL Color Vial Empty 4.86 4.90 4.83 4.89 4.85 4.95 4.83 Time (Min.)  0 6.05 6.12 6.07 6.10 6.04 6.11 6.07  1 6.05 6.12 6.07 6.10 6.04 6.11 6.07  2 6.05 6.12 6.07 6.09 6.04 6.11 6.07  3 6.05 6.12 6.07 6.08 B 6.04 6.11 6.07  4 6.05 6.12 6.07 6.08 6.04 6.11 6.08  5 6.05 6.12 6.07 6.07 6.04 6.11 6.07  6 6.05 6.12 6.07 6.07 6.04 6.11 6.07  7 6.05 6.12 6.07 6.06 6.04 6.11 6.05  8 6.05 6.12 6.07 6.06 6.04 6.11 6.04  9 6.05 6.12 6.07 6.06 6.04 6.11 6.04 10 6.05 6.12 6.07 6.05 6.04 6.11 6.03 15 6.05 6.12 6.07 6.04 6.04 6.11 5.98 20 6.05 6.12 6.07 6.04 6.04 6.10 5.95 wt loss 0 0 0 .06 mg 0 .01 0.12 g sample 1997S13 0 6.06 5000 ppm 1 6.06 2 mL Fe 2.00 2 6.06 New 3 6.06 Stabilizer 100.3 4 6.05 1997S 5 6.05 HB 1220 6 5.92 7 5.82 Vial 4.87 8 5.80 9 5.79 10 5.79 15 5.79 20 5.79

[0042] 1997S9=1 mL 1997 Stabilized HBase 55% HA, 100 mL of 1,4,8,11 Tetraazacyclotetradecane-1,4,8,11-tetracetic acid (Aldrich 40,040-8) 100.9 mg/10 mL H₂O, 2 mL of 5000 ppm Fe(III)

[0043] 1997S13=1 mL 1997 Stabilized HB 55% HA, 100 mL of 4,5 Dihydroxy-1,3-benzene disulfonic Acid, disodiumsalt (Aldrich 17,255-3) 106.3 mg/10 mL H₂O, 2 mL 5000 ppm Fe(III)

[0044] 1997S 16=1 mL 1997 Stabilized HB 55% HA, 100 mL of Ethylene bis(oxyethylenenitriolo)-tetraacetic acie (40991-0250) 99.4 mg/10 mg H₂O, 2 mL of 5000 ppm Fe(III)

[0045] 1997S22=1 mL 1997 Stabilized HBase 55% HA, 100 mL of 1,4,8,11-tetraazacycloetradecane-5,7-dione (33,316-6 cat#) 102 mg/10 mL, 2 mL of 5000 ppm Fe

[0046] 1997S24=1 mL 1997 Stabilized HBase 55% HA, 100 mL of 4,8-Dihydroxy quinoline-2-carboxylic acid 99.6 mg/10 mL, 2 mL of 5000 ppm Fe

[0047] 1997S11=1 mL 1997 Stabilized HBase 55% HA, 100 mL of 4,7 dihydroxy 1,10 phenanthroline 51.3 mg/10 mL, 2 mL of 5000 ppm Fe(III)

[0048] 1997S25=1 mL 1997 Stabilized HBase 55% HA, 100 mL of Inositol hexaphosphoric acid (40-50% Sol'n) 187 mg/10 mL, 2 mL of 5000 ppm Fe

[0049] 1997S15=1 mL 1997 Stabilized HBase 55% HA, 100 mL of 1,4,10,13-tetroxa-7,16-diazacyclooctadecane (29,580-9 Aldrich) 104.3 mg/1 mL H₂O, 2 mL of 5000 ppm Fe

Gas Evolution+Titration of New Stabilizer

[0050] sample 1997S41 1997S42 1997S39 1997S38 1997S37 5000 ppm 1.94 mg 2.09 mg 1.70 mg 2.07 mg 2.22 mg Fe 2 mL New Stabilizer Σ 1023 mg 97.7 mg 100.4 mg red 100 mg Green 100 mg 100 mL 1997S 56% Σ 1224 mg 1221 mg 1238 mg light 1224 mg light 1238 mg HA 1 mL yellow orange empty Vial 4.85 g 4.87 g 4.95 g 4.82 g 4.88 g Time (Min.)  0 6.06 6.08 6.17 6.05 6.11  1 6.06 6.08 6.17 6.05 6.11  2 6.06 6.08 6.17 6.05 6.11  3 6.06 6.08 6.16 6.05 6.11  4 6.04 6.08 6.14 6.05 6.11  5 6.03 6.07 6.11 6.05 6.11  6 5.98 6.07 6.05 6.05 6.11  7 5.88 6.07 5.99 6.05 6.11  8 5.82 6.06 5.95 6.05 6.11  9 5.78 6.06 5.94 6.05 6.11 10 5.76 6.06 5.93 6.05 6.11 15 5.75 6.05 5.92 6.05 6.11 20 5.74 6.04 5.91 6.05 6.11 wt loss 0.32 g 0.04 g 0.26 g 0 mg 0 g

[0051] 1997S41=1 mL 1997 Stabilized HBase 56% HA, 100 mL of (±)Cis-Epoxytricarbollylic acid 100 mg/10 mL, 2 mL of 5000 ppm FE(III)

[0052] vial+¾ mL HCl→200 mL, 10 mL aliquot

[0053] 1997S42=1 mL 1997 Stabilized HBase 56% HA, 100 mL of N-(2-Acetamidaminodiacetic acid 105 mg/10 mL, 2 ml of 5000 ppm Fe(III) $\begin{matrix} {HCL} & 5.209 \\  + & \quad \\ {\quad {{NH}_{3}{OH}}} & 8.160 \\  + & \quad \\ {NH}_{4} & 8.563 \end{matrix}\quad \begin{matrix} \quad \\ {2.951\quad {mL} \times 15} \\ \quad \\ {0.403\quad {mL} \times 7.7} \\ \quad \end{matrix}\quad \begin{matrix} \quad \\ {44.3\% \quad {HA}\quad {NH}_{2}{OH}} \\ \quad \\ {3.1\% \quad {NH}_{3}} \\ \quad \end{matrix}$

[0054] 1997S39=1 mL 1997S Stabilized 56% HA, 100 mL of Salicylic Acid 7.8 mg/10 mL, 2 mL of Fe(III) 5000 ppm

[0055] 1997S38=1 mL 1997S Stabilized 56% HA, 100 mL of Thiosalicylic acid 101.6 mg/1 mL, 2 mL of 5000 ppm Fe(III)

[0056] 1997S37=1 mL 1997S Stabilized 56% HA, 100 mL of CDTA 112 mg/10 mL, 2 mL of 5000 ppm Fe(III)

New Stabilizer Screening Gas Evolution+Titration

[0057] sample 1997S43 1997S45 1007S46 2 mL 500 ppm Fe(III) 1.80 mg 100 mg 1.93 new stabilizer 100 mL 100 mg 100 mg 100.7 1997S H-base 56% 1223 mg 1229 mg 1232 Hydroxylamine Vial min 4.83 g 4.91 g 4.92 g 0 6.06 6.11 6.15 1 6.06 6.11 6.15 Note: After wt loss content 2 6.06 6.12 6.15 of vial transferred to 200 mL 3 6.05 6.12 6.15 Volumetric Flask, 3-4 mL 4 6.04 6.12 6.15 5 6.02 6.12 6.15 Conc HCl Aldrich, diluted 6 6.00 6.12 6.15 7 5.98 6.12 6.15 to volume, 10 mL aliquot 8 5.95 6.12 6.15 titrated using 0.25 NaOH 9 5.93 6.12 6.15 10 5.91 6.12 6.15 15 5.88 6.12 6.15 20 5.86 6.12 6.15 wt loss 0.20 g 0 g 0 g

[0058] 1997S43=1 mL 1997S 56% HA, 100 mL of 2-Carboyethylphosphonic acid, 2 mL of 5000 ppm Fe(III) $\begin{matrix} {HCl} & {3.660\quad {mL}} \\  + & \quad \\ {\quad {{NH}_{3}{OH}}} & {4.914\quad {mL}} \\  + & \quad \\ {NH}_{4} & {5.526\quad {mL}} \end{matrix}\quad \begin{matrix} \quad \\ {{1.254\quad {mL} \times 15} = {18.8\% \quad {HA}}} \\ \quad \\ {{0.612\quad {mL} \times 7.7} = {4.7\% \quad {NH}_{3}}} \\ \quad \end{matrix}$

[0059] 1997S45=1 mL 1997S 56% HA, 100 mL of Mercaptonicotinic Acid 97.9 mg/10 mL, 2 mL of 5000 ppm Fe(III) ${{\begin{matrix} {HCl} & 2.704 \\  + & \quad \\ {\quad {{NH}_{3}{OH}}} & 6.314 \\  + & \quad \\ {NH}_{4} & 0 \end{matrix}\quad 3.61\quad {mL} \times 15} = {54\% \quad {HA}}}\quad$

[0060] 1997S46=1 mL 1997S 56% HA, 100 mL of cyxtine 96 mg/10 mL 2 mL of 5000 ppm Fe(III) $\begin{matrix} {HCl} & 2.767 \\  + & \quad \\ {\quad {{NH}_{3}{OH}}} & {6.232 = {3.465 \times 15}} \\  + & \quad \\ {NH}_{4} & {6.379 = {0.147 \times 7.7}} \end{matrix}\quad \begin{matrix} \quad \\ \quad \\ {52\% \quad {HA}} \\ \quad \\ {1.1\% \quad {NH}_{3}} \end{matrix}\quad \begin{matrix} \quad \\ \quad \end{matrix}$ 

I claim:
 1. A stabilized hydroxylamine solution comprising a selected stabilizer selected from the group consisting of (a) diethylenetriaminepentaacetic acid (b) triethylenetetraminehexaacetic acid (c) ethylenebis(oxyethylenenitrilo)-tetraacetic acid, (d) 1,4,8,11-tetraazacyclotetradecane-1,4,8-11-tetraacetic acid, (e) 4,8-dihydroxyquinoline-2-carboxylic acid, (f) 4,5-dihydroxy-1,3-benzenedisulfonic acid, (g) 4,7-dihydroxy-1,10-phenanthroline, (h) 2-mercapto-nicotinic acid 1,4,8,11-tetraazacyclotetradecane-5,7-dione, (i) bis[N,N-bis(carboxymethyl)-aminomethyl]fluorescein, (j) N,N′-bis(2-carboxyethyl)-N,N′ethylenediglycine trihydrate, (k) cystine, (1) 2,3-dihydroxybenzoic acid, (m) thiosalicylic acid and any mixture of the foregoing.
 2. The stabilized solution as defined in claim 1 wherein said stabilizer is present in said solution in an amount ranging from about 0.005 percent to about 0.1 percent by weight to the total weight of the stabilized solution.
 3. A method of stabilizing a hydroxylamine solution which comprises adding at least one selected stabilizer to the solution.
 4. The method as defined in claim 1 wherein said stabilizer is selected from the group consisting of (a) diethylenetriaminepentaacetic acid, (b) triethylenetetraminehexaacetic acid, (c) ethylenebis(oxyethylenenitrilo)tetraacetic acid (“EGTA”), (d) 1,4,8,11-tetraazacyclotetradecane-1,4,8-11-tetraacetic acid, (e) 4,8-dihydroxyquinoline-2-carboxylic acid, (f) 4,5-dihydroxy-1,3-benzenedisulfonic acid, (g) 4,7-dihydroxy-1,10-phenanthroline, (h) 2-mercaptonicotinic acid, (i) bis[N,N-bis(carboxymethyl)-aminomethyl]fluorescein, (j) N,N-bis(2-carboxyethyl)-N,N′ethylenediglycine trihydrate, (k) cystine, (1) 2,3-dihydroxybenzoic acid, (m) thiosalicylic acid and any mixture of the foregoing.
 5. The method as defined in claim 4 wherein said stabilizer is added to yield an amount thereof in the solution of about 0.005 percent to about 0.1 percent by weight to the total weight of the solution. 